Arbor



A. BUESCHER March 11, 1952 ARBOR 2 SHEETS-SHEET i2 Filed May 20, 1946 IKNVENTOR.

Patented Mar. 11, 1952 yz claim. 1

This invention relates to Jarbors Vor `mandrelsy andhas more especial reference to qsuch devices :which support tubular work and 1wherein it is desirable to expand the mandrel or arbor .throughout an extended area or material length Hoi' the bore of thevwork in order toattain moreor less'even pressure throughout the bore, thus enabling such'pressure to relatively light and of a'nature not tomar, distort, or disgure the work.

Generally, the expanding :arbors or mandrels `as heretofore constructed, Yapull-in tapered ex- L panderhas been utilized which exerted most of its expanding -eiect onthe outer -end portion of lthe .arbor or mandrel and frequently called for a degree of pressure which `resulted inthe formation of undesirable pressure marks on `the bore of the work, and which in some cases were inadmissible Aso `that the usesof such `expanding ar- .bors or mandrels have been limited.

This application is a continuationf-,in-part of my abandoned application, Serial No. 541,245,

filed June 20, 1944, for Arbors.

The Vpresent invention so disposes an expander ,element within the arbor -or mandrel :that eX'n panding pressure may be .exerted remote from the end thereof .and preferably at spaced intervals along the length thereof; andinore particularly provides an expander having taperedsteps in its length enacting against tapered seats within the arbor or mandrel toprovide spaced points orzonesof expanding pressure along the length of the device.

VA prime object is to .provide an arbor or mandrel of `the Ypresent character which has a pilot portion to facilitate rapid and accurate `positioning of the Work thereon, aided by a normally contracted tapered portion extendingffromsaid pilot portion to the fouter free ,end of the arbor, and

`incombination with anexpander Yfor thelatter.

Further, the said invention provides adjustable means limiting longitudinal arbor-expanding movement of the expander to prevent4 undue and inadvertent expansion `of the device beyond a predetermined limit.

Sti1lfurtherthe said invention-affords a seat in the outer ,endof the arbor or mandrel to cooperate with asupporting center in providing for ,expansionfoi that end of :the saidrarbor or `Inandrel in `ermibinaton with `provision for expansion of the mandrel vata point or points remote from that end.

Additional or subsidiary objects and `advantages resulting :from the construction or operation of the invention as `it.inay be carried `into effect will become v@parent as thesaidinvention is hereinafter further disclosed and Ait 'will be noted that ,invention is lpeuticularly, but not necessarily solely, intended Yfor use on hydraulically operated machines.

:In `carrying the said invention into efEect,-I. may

`provide an arbor or mandrel, havingla work-,receiving portion divided radially throughout a major part of its length from one end for expan- :sion within tubular work, whichportion'iscontractile to ataper-smallerat its outer or free end,

rand-Which portion extendsfrom a work-positioning lnon-contractile pilot portion, with -an -expanderin the iormoi a rod having conical steps thereon within the arbor or mandrel, the said `conical steps being `opposed Vby corresponding conical seats ontand within `the arboigsaid `rod being threaded .into the inner `end of thedevice so that said rod may be screwed into `arbor-expanding impingement witlrthe aforesaid conical :seats to an extent .limited by adjustable stop means,` anda conical seat on the outers'lott-ed-end ofthe arbor to receive the-conicalendofla-center. All `of which is `more particularly described andascertained hereinafter, by way of example, having reference to the acconflpanying ,-drawing, wherein:

Figure `l isla longitudinaltsectional elevationof an arbor -or mandrel ,embodying the said =inven tion (the spring jaws `being contracted) l together with, the cperatingrneans;

Alfigure 42 fis a :longitudinal` section of .the principaltparts ofrliigure l,.the spring wjaws being `en- .-gaged witha center and expanded towork-engag ing position;

Figure `3 is .a side-'elevationlof Vthe arbor with its jaws contracted;

vEigure 4 is .an -end elevation of the arbor `with its jawscontracted and ,igures .5 and l 6, respectively, arefcross sections `talienon the -planesof-lineE--SandiG-B of Fig- Similar characters `of Areference indicate simi- `lar parts in `theseveral figures of the drawing.

The numeral .5 indicates -in general :ansarbor `or mandrel,which inrthis case islprovidedwitha driving portion t unitary with `a driver head l and which 4rnay-.opti.onally be separate from vor integral `with fthe arbor-5. :Said head 'I Vis attached,

forexanipla toardriyertby means-of screws 9 passing through lenlarged operiilfies I0 inthe head 1'! and `permitting concentric or eccentricadjustment of said head through actuation of any -desired number of screws ,i l carried i by y,the driver.

Said mdriver 8 is mounted infany sui-table ,manner Y so as torotate the arbor ormandrel.

um, and 2li.

mounted .on ,the Isaid arbor or mandrel ,ngers l5, l5, ,and LH are inherently resilient so A :work-receiving portion i! of thearbor or mandrel ,is shown as being radially slotted throughout the major `part of `its length from -the `front orfdistal end,ras indicatedby reference characters `t5, i6, `and l1, .thereby formingany conventional asto `be Abiased .to contract, `even tothe point of mutually contacting at the said front or distal end of portion `i4, and `the latter portion is thus tapered `with ,its .distal end smaller than the proximal or pilot c end.

fIt is :especially to .be noted that said .portion i4 drical pilot portion I2 is provided. This portion I2 is important because after the work is applied over the tapered portion of the mandrel, it is snugly engaged by the pilot portion and accurately held while said portion I4 is expanded to grip and hold it.

Extending into the said mandrel from the rear end thereof is an expander in the form of a rod 22 provided at the forward end with an extension 23 of smaller diameter, the step between the parts of larger and smaller diameter 22 and 23 being coned or tapered, as at 24, and the distal end of the extension 25 being also coned or tapered as at 25. The rod 22 is slidable in the arbor and is operated manually or by power, for example, by means of screw threads 26 being attached to a plunger I3 of a-'conventional hydraulic cylinder D. Engaged with said threads 26 are adjustable.

locknuts 21 and 28 to act as stops to limit the extent or insertion of the expander rod into the arbor or drill.

Said arbor or mandrel and its resilient fingers are bored in counterpart of the expander rod 22 and its extension in such manner that conical or tapered seats 29 and 30 are provided to receive the conical or tapered steps 24 and 25 of the expander rod whereby, upon the said rod being moved into the arbor or mandrel to the required extent, the same expands the resilient ngers I8, I 9, and 20 of the said arbor or mandrel at the seats 29 and 30, as will be readily understood.

The outer end of the resilient ngers of the arbor or mandrel is`also provided with a conical seat 3l to receive the conical point of a center 32 which may also act as an expanding agent for the outer end of the said fingers when the outer end of the arbor or mandrel is pressed into supported engagement with the center in the usual manner.

It will be easily seen that the construction described provides for radial expansion of the fingers by internal pressure at a plurality of points or zones in their length insuring more even distribution of pressure throughout an extended area along the bore of the work in contrast to such expansion usually at a single point, andV especially merely at or about the end portions of the arbor or mandrel as has heretofore been the general practice. As a result, in the present arrangement, the concentration of pressure at any point on the work may be lighter with equal holding effect, the slotting of the fingers may be quite fine or narrow and the tendency to produce pressure marks in the bore of the work greatly minimized.

Further, the provision of stops limiting the rectilinear expanding movement of the expander rod prevents undue pressure being applied to the work or breakage or distortion of the arbor or mandrel being brought about by careless application of expanding pressure to the fingers thereof in the absence of work supported thereon. Such spoilage of arbors or mandrels has heretofore been very high and costly.

It may be pointed out that this device is well adaptable to the particular ,iob so that the utmost in accuracy mayn be attained and scoring, pressure marks, and so forth, such as have resulted from the use of the prior art devices may be avoided.

In so machining or fitting the device to the work, the bore of which has been determined, the arboris expanded by means of the rod 22 in a grinding machine and is then ground while so expanded accurately to an O. D. which constitutes a light but eiective driving t for the Work. Thus, when the said rod 22 is partially withdrawn thereafter, thelarbor will contract to tapered form, except for the pilot or butt portion l2, so that in use a succession of identical pieces'of work may be quickly positioned onto the pilot or butt portion of the arbor, the rod 22 moved hydraulically into its arbor expanding position to the extent determined by the stop means 21, and the O. D. of the work thereafter ground accurately in relation to the bore with a minimum of manipulation and adjustment.

While not necessarily so limited in scope, the device is particularly suitable for the grinding of soft'm'etal tubular sleeves such as valve guides wherein it is important that the previously ground bore should be in no way damaged or distorted, thus avoiding the exceedingly high spoilage on these parts unavoidable with the prior art.

This invention may be developed within the scope of the following claims, without departing from the essential features of the said Vinvention, and it is desired that the specification and drawing be read as being merely illustrative of a practical embodiment of the said invention and not in a strictly limiting sense.

What I claim is: v

1. In an arbor for internally supporting tubu lar work, a cylindrical work-holding body radially slotted from one end only to provide a plurality of expansion fingers all mutually connected at the other end of said body to form an expanding and non-expanding work-receiving arbor proportioned to t within one end of the bore of the work, driving means connected to the non-expanding end portion of said body, and a 'ngerexpanding rod longitudinally adjustable within said body, said rod having a plurality of tapered successively enlarged steps disposed axially thereon and said fingers having correspondingly positioned tapered and successively enlarged internal seats thereon for expanding engagement by said steps.

2. In an arbor for internally supporting tubular Work, a cylindrical work-holding hollov7 body longitudinally slotted inwardly from one end and short of the other end of the work-holding portion of said bdy, said body between the slots and second-mentioned end having a work-engaging non-expandable pilot portion of approximately cylindrical form proportioned to fit Within one end of the bore of the work, said body being inherently resilient to contract at the first-mentioned end to a normally tapered form, an eX- pander rod operable in the hollow of said body having a plurality of spaced steps thereon, and said body having seats engageable by said steps in expanding said body, whereby said body may be expanded from its normally tapered form to a substantially non-tapered cylindrical form.

ARTHUR BUESCHER.

REFERENCES CITED The following references are of record in the iile of this patent:

- UNITED STATES PATENTS 1,919,239 McFall July 25, 1933 

